(1) Field of the Invention
The present invention relates to an equine vaccination method wherein the vaccine is potentiated by a leukokine or mixed leukokines administered with the vaccine. In particular, the present invention relates to the potentiation of an equine influenza vaccine with mixed equine leukokines.
(2) Prior Art
The prior art relating to interferon is extensive. U.S. Pat. No. 3,699,222 (1972) to Isaacs and Lindenmann describes the original research with interferon as an antiviral agent. U.S. Pat. No. 4,503,035 (1985) to Pestka and Rubinstein describes purified interferons and in particular the use of leukocytes and a virus (Newcastle Disease virus) for inducing the interferons. Example 7 of this patent particularly describes the use of this procedure to produce equine interferbn.
The term "interferon" is generally used by the prior art to refer to induced proteins of leucocyte and of fibroblast origins which interfere with viral replication. The terms "leukokine" or "leucokine" have been used in the recent literature to characterize proteins including interferons of leukocyte origins and the term leukokine is used herein.
The presence of interferons in the blood stream with virus vaccines is known to increase or enhance the immune antibody response. U.S. Pat. No. 3,906,092 to Hilleman, Tytell and Woodhour (1975) describes the use of interferon inducing polynucleotides as adjuvants to non-replicating (killed virus) vaccines to enhance antibody formation. The administration of mixed live Newcastle disease virus vaccine and interferon to provide an enhanced protection for chickens is described as prior art in this patent, but there is no description of the administration of interferon and a non-replicating virus vaccine. It is not believed that the use of interferons with equine vaccines has been described by the prior art.
Vaccination with commercially available inactivated equine influenza virus vaccine alone (consisting of killed virus of tissue culture origin) produces a variable humoral immune antibody response in equines. This variation is in the magnitude of the antibody response, the time course in which the equine responds to the vaccine, and the duration of the antibody response. These variations have been recognized and accepted as due to biological variation of the species' immune system. Where there is an urgent need for immunity, the equine is repeatedly vaccinated with influenza vaccine.
New and more potent vaccines which augment the equine's immune response to influenza or other viral vaccine vaccination and thereby greatly increase both the likelihood and extent of a protected period with less frequent vaccination, are needed. Further, vaccines are needed where there is a less variable response to the vaccination.